This invention relates to a device for determining the flow rate of metallic paramagnetic and ferromagnetic particles.
Heretofore devices for measuring the flow rate of a mass of metal particles, such as shot, made use of two selectively spaced inductive coils. The coils were magnetically coupled with one coil acting as the primary with some convenient time-varying current excitation and the second coil acting as a secondary with a volt meter as a load. As the flow of particles through the coupled coils increases, the mutual magnetic coupling increases with such increase being displayed on the volt meter. The volt meter reading is then scaled to indicate the rate of mass flow of the particles.
In the above described prior art two-coil method of flow rate measurement both coils must be mounted concentrically and spaced a selected distance for accurate measurements. Additionally, at low particle flow rates, the mass of the particles passing through the coils is generally not enough to create a sufficient mutual magnetic coupling between the coils. Therefore, at low particle flow rates an erroneous reading is obtained by using the two-coil arrangement.
The following describes an improved mass flow rate detector which utilizes only a single coil and which is extremely accurate in measuring low, as well as high flow rates of metal particles.